Aircraft, particularly commercial passenger aircraft, are commonly equipped with a fire protection system in the cargo compartment. A typical fire protection system comprises two sub-systems: a fire detection system and a fire suppression system. The fire detection system includes one or more fire detectors (e.g., smoke detectors) and the fire suppression system includes a fire suppression agent. When a fire is detected in the cargo compartment, the fire suppression agent is released and floods the cargo compartment with an appropriate quantity of the fire suppression agent. The release of the fire suppression agent may occur automatically in response to a positive fire detection by a fire detector or, alternatively, may occur in response to manual pilot intervention (e.g., after the pilot receives a warning signal and actuates one or more switches).
Halon 1301 (bromotrifluoromethane) has long been the fire suppression agent of choice on aircraft. Halon 1301 is a clean fire suppression agent; it does not damage cargo or leave behind a residue. Furthermore, unlike inert gas-based fire suppression agents, such as carbon dioxide, Halon 1301 is effective in suppressing fires at relatively low concentrations (e.g., 3 to 10 percent by volume). Therefore, a breathable level of oxygen may remain after discharge of Halon 1301.
Halon 1301 has a relatively high ozone depletion potential (“ODP”) and alternatives are being sought out. Several alternatives to Halon 1301 have been proposed, such as 2-bromo-3,3,3-trifluoro-1-propene. However, the alternatives proposed to date have been unsuitable for aircraft use because they cannot pass the United States Federal Aviation Administration's Aerosol Can Explosion Simulation Test, which is outlined in the Federal Aviation Administration's Minimum Performance Standard for Aircraft Cargo Compartment Halon Replacement Fire Suppression Systems, 2012 Update (DOT/FAA/TC-TN12/11).
Accordingly, those skilled in the art continue with research and development efforts in the field of aircraft fire suppression.